Recently, a high-power and high-energy density lithium ion battery has been demanded not only for consumer appliances such as cellular phones, but also as a power source for hybrid cars capable of efficiently utilizing energy.
With regard to a binder resin (adhesive) that bonds an electrode active material and a metal foil to each other in a lithium ion battery, polyvinylidene fluoride (PVDF) which is hardly degraded even if it is in contact with an electrolytic solution is described in Patent Literatures 1 and 2.